1. Field of the Invention
The present invention relates to apparatus adapted to absorb or to utilize the energy of sea waves.
2. Prior Art
To that end many different types of apparatus have already been proposed, comprising a floating or submerged moveable, water displacing member, mounted on devices connected to land or to the sea bottom, and which oscillates in step with the fluctuating force from the wave. Such a water displacing member may, for instance, be a floating bouy which performs vertical oscillations in the sea. The disadvantage of most previously proposed apparatus is that the displacement of a member is essentially in step with the displacement of the wave at the location of the member, i.e. that the displacement curve of the member in time essentially coincides with the local elevation curve of the sea. As a result, part of the power which the member absorbs from the wave during one part of the oscillation cycle is lost during another, i.e. the member is an inefficient wave power absorber. However, significantly improved efficiency can be obtained if the velocity curve of the member, instead of following the displacement curve, is made to coincide in time with the local elevation curve of the sea. This means that said displacement curve must be properly delayed with respect to the elevation curve of the sea. Moreover, additional improved efficiency is obtained if also the magnitude of the displacement of the water displacing member is controlled relative to the magnitude of the wave.